Coolant application device

ABSTRACT

A coolant application device includes a nozzle which spouts coolant and a motor which adjusts the rotation angle of the nozzle. The coolant application device also includes a housing, a hollow shaft rotatively and fluid-tightly inserted into the housing, a coolant passage formed in the hollow shaft, a port arranged at a lateral wall of the hollow shaft and communicating with the coolant passage, and an inlet passage arranged in the housing and communicating with the coolant passage through the port. The nozzle is connected to the hollow shaft and communicates with the coolant passage. The hollow shaft is coaxially arranged and directly connected to an output shaft of the motor.

BACKGROUND OF THE INVENTION

This application is a continuation application of U.S. Patentapplication Ser. No. 13/430,039, filed Mar. 26, 2012, which claimspriority to JP 2011-097405, filed Apr. 25, 2011. The disclosures of eachof these applications are herein incorporated by reference in theirentireties.

FIELD OF THE INVENTION

The present invention relates to a coolant application device forapplying coolant to the processing area of workpiece when machining theworkpiece with a machine tool.

DESCRIPTION OF THE RELATED ART

In general, when conducting machine works such as cutting or grindingwith machine tools, the machine works are processed while supplyingcoolant to the processing area of the workpiece for lubrication,cooling, chip removal, metal adhesion prevention, etc. In the machineworks, for ensuring the stability and precision of the process, it isdesired that coolant is properly supplied to the processing parts of theworkpiece. Here, as explained in Japanese Patent Application Laid-openNo. 2002-18674 and U.S. Pat. No. 6772042, in automatic machine toolssuch as machining centers or other NC machine tools, different types ofcoolant application device with adjustable coolant nozzle angle havebeen proposed. With these types of coolant application device, whichallow the coolant nozzle angle to be automatically adjusted according tothe development of metalworking process, coolant is properly supplied tothe processing area of the workpiece.

In the above kinds of the coolant application device, a nozzle whichspouts coolant is rotated by a servomotor. By adjusting the position andthe angle of the nozzle after a tool change or according to thedevelopment of machining process, coolant is precisely applied to theprocessing area of the workpiece.

Since the coolant application device tend to be exposed to coolantdroplets or chip dispersion during machine works, the servomotor drivingthe nozzle, the reduction gear device, etc. need to be provided withsufficient waterproof and dust-resistance properties. Further, since thecoolant application device needs to be mounted in a limited space of theautomatic machine tools such as machining centers or other NC machinetools, downsizing of the coolant application device has been demanded.

SUMMARY OF THE INVENTION

The present invention has been made in view of the above circumstances,and it is an object of the present invention to provide a coolantapplication device which has excellent waterproof and dust-resistanceproperties while achieving requirements to be downsized.

Embodiments according to the present invention hereinbelow exemplifysome structures of the present invention, and are itemized forfacilitating understanding of various structures of the presentinvention. Each item does not intend to limit the technical scope of thepresent invention. While considering the best modes to carry out thepresent invention, even if components of each item is partiallysubstituted or deleted, or even if another component is added thereto,these should be regarded as the elements of the technical scope of thepresent invention.

In order to achieve the object described above, the present inventionprovides a coolant application device including a nozzle which spoutscoolant and a motor which adjusts the rotation angle of the nozzle. Thecoolant application device also includes a housing, a hollow shaft whichis rotatively and fluid-tightly inserted into the housing and has acoolant passage therein, a port which is arranged at a lateral wall ofthe hollow shaft and communicates with the coolant passage, and an inletpassage which is arranged in the housing and communicates with thecoolant passage through the port. The nozzle is connected to the hollowshaft and communicates with the coolant passage. The hollow shaft iscoaxially arranged and directly connected to an output shaft of themotor.

Since the coolant supplied from the inlet passage will flow into thecoolant passage of the hollow shaft through the port arranged at thelateral wall of the hollow shaft, the fixed inlet passage does not needto be connected directly with the rotatable hollow shaft by means ofjoint parts. Accordingly, it is possible to prevent the leakage ofcoolant due to defects of the joint parts. Further, since the coolant issupplied to the nozzle through the hollow shaft, the coolant applicationdevice can be downsized. Still further, since parts to be sealed areminimized, it is possible to improve drip-proof properties anddust-resistance properties.

In one aspect of the present invention, the hollow shaft and the outputshaft of the motor are integrally formed as one piece.

Because of the integration of the hollow shaft and the output shaft ofthe motor, it is possible to reduce the number of parts.

In another aspect of the present invention, the motor is a steppingmotor.

Since the stepping motor is used, it is possible to perform an open-loopcontrol, contributing to the simplification of the control circuit.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a coolant application device accordingto the first embodiment of the present invention;

FIG. 2 is an A-A cross sectional view of the coolant application device;

FIG. 3 is a plan view of the coolant application device where a coverthereof is removed;

FIG. 4 is a perspective view of the coolant application device where thecover thereof is removed;

FIG. 5 is an exploded perspective view of the coolant applicationdevice;

FIG. 6 is a cross sectional view of a coolant application deviceaccording to the second embodiment of the present invention; and

FIG. 7 is an exploded perspective view of the coolant application deviceof the second embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will be explained hereinafter withreference to the accompanying drawings. To begin with, the firstembodiment of the present invention is explained based on FIGS. 1 to 5.A coolant application device 1 of the first embodiment is mounted at anumerically controlled (NC) machine tool such as an NC drilling machine,an NC milling machine, an NC lathe, a machining center, etc. so as toapply coolant to the processing zone of workpiece. In the coolantapplication device 1, a housing 14 and a motor 4 are integrally housed(unitized) in a case 2.

The case 2 looks approximately like a rectangular solid and is composedof a box-shaped case main body 5 which has one open side, and a cover 6which seals the open side of the case main body 5. In the case 2, arectangular mounting portion 7 is formed integrally with the case mainbody 5. The mounting portion 7 extends to form a flat plate continuingthe cover 6. The mounting portion 7 is provided with a pair of elongatedholes 8, 8 by which the case 2 is mounted to automatic machine tools,etc.

The interior of the case 2 is divided by a sealing plate 9 which isformed integrally with and extends in a longitudinal direction of thecase main body 5. Further, in the case main body 5, a wiring chamber 10is formed next to the chamber in which the housing 14 and the motor 4are housed. The wiring chamber 10 serves for wiring the lead wiresconnected to the motor 4. Approximately U-shaped cutouts 11, 12 are eachformed respectively at the sealing plate 9 and at the lateral wall 5A ofthe case main body 5 (the lateral wall closer to the housing 14). Anopening 13 (see FIG. 2) is formed on the lateral wall 5B (see also FIG.2) of the case main body 5 facing the cutout 12 of the sealing plate 9.At the end of the case main body 5 where the motor 4 is positioned, aclearance 9A for connecting the lead wire to the motor 4 is formed.

The cover 6 is mounted on the opening portion of the case main body 5 bymeans of a well-known fixing means (not shown) such as screws,fasteners, adhesives, etc. The case main body 5 and the cover 6 aresealed to each other by means of a well-known sealing means (not shown)such as packing. The cover 6 is preferably mounted on the case main body5 in a removable manner by means of a removable fixing means such asscrews, and the like. The case 2 is made of any appropriate materialssuch as synthetic resin, aluminum alloy, steel, etc.

The housing 14 has an external shape of an approximately rectangularsolid. A stepped opening portion which includes a large diameter bore15A and a small diameter bore 15B penetrates into the housing 14. Acylindrical guide member 16 is fluid-tightly fitted into the largediameter bore 15A while a nozzle chamber 17 is formed between the smalldiameter bore 15B and the guide member 16. A hollow shaft 18 whichpenetrates the housing 14 is rotatively and fluid-tightly inserted intothe small diameter bore 15B and the guide member 16. The hollow shaft 18is rotatively supported by bearings 19, 20 arranged at both ends of thehousing 14. The hollow shaft 18 and the small diameter bore 15B, and thehollow shaft 18 and the guide member 16 are each sealed by means of anO-ring 21 and an O-ring 22, respectively.

The hollow shaft 18 has a coolant passage 23 which extends along thecentral axis of the hollow shaft 18. One end of the coolant passage 23opens at one end of the hollow shaft 18 while the other passage end isclosed. Further, a plurality of ports 24 are provided on the lateralwall of the hollow shaft 18, which enables the coolant passage 23 andthe nozzle chamber 17 to communicate with each other. An inlet passage25 is provided on the lateral wall of the housing 14 so as tocommunicate to the nozzle chamber 17 while a cylindrical inlet duct 26is connected to the inlet passage 25. A nozzle 27 is connected to theopen end of the hollow shaft 18, the nozzle 27 being directedperpendicularly relative to the hollow shaft 18. Consequently, thecoolant passage 23 communicates with the interior of the nozzle 27. Aprotruding joint 28 with two flat faces is formed at the closed end ofthe hollow shaft 18. At the end of the housing 14 (the side where thelarge diameter bore 15A is positioned), a convex rear cover 29 with anopening is fitted. The closed end of the hollow shaft 18 is insertedinto the opening of the rear cover 29. The housing 14 is mounted on thecase main body 5 in such a manner that 1) the open end of the hollowshaft 18 to which the nozzle 27 is connected is inserted into the cutout11, and 2) the inlet duct 26 is inserted into the cutout 12 and theopening 13.

The motor 4 is configured as that its external shape is like arectangular solid approximately similar to the housing 14. Further, thefirst end of the output shaft 30 is provided with a grooved joint 31which is engaged with the protruding joint 28 configured at the closedend of the hollow shaft 18. The motor 4, which can be a well-known servomotor or stepping motor, controls the rotation angle of the output shaft30. Further, in the stepping motor, a variable reluctance type, apermanent magnet type, or a hybrid type which is a combination of theprevious two types may be used. In the present embodiment, a hybrid typestepping motor is used since the adjustable step angle is sufficientlysmall. A lead wire (not shown) which supplies control current isconnected to the motor 4. The lead wire extends into the wiring chamber10 passing through the clearance 9A of the sealing plate 9, and furtheris connected to an external drive circuit (not shown) through anelectrical connector (not shown) mounted on the outer wall of the case2.

In the motor 4, its front cover 32 is engaged with the rear cover 29 ofthe housing 14 while the rear cover 33 of the motor 4 is abutted to andfixed at the inner surface of the lateral wall 5C of the case main body5. Here, in FIG. 2, the reference numeral 34 indicates a rotor which isconnected to the output shaft 30, the reference numeral 35 is a statorwhich is arranged so as to face the periphery of the rotor 34, and thereference numeral 36 is a bearing which rotatively supports the outputshaft 30.

The housing 14 and the motor 4 are integrally housed in the case mainbody 5 in such a manner that the output shaft 30 of the motor 4 isinserted into the rear cover 29 on the side of the housing 14; and thejoint 31 of the output shaft 30 is engaged with the joint 28 of thehollow shaft 18. The housing 14 and the motor 4 are then both fixed tothe case 2 by which the cover 6 is mounted on the opening portion of thecase main body 5. Here, the contour of the joint 28 of the hollow shaft18 and the contour of the joint 31 of the output shaft 30 are notlimited to the double-face configuration. Instead, as long as the joint28 and the joint 31 are able to transmit the rotation from the outputshaft 31 to the hollow shaft 18, any other shape is applicable.

While directing the nozzle 27 in a proper direction, the coolantapplication device 1 thus structured is installed in automatic machinetools such as machining centers or other type of NC machine tools, byinserting bolts into the elongated holes 8 of the mounting portion 7.Further, the inlet duct 26 is connected to the coolant supply sourceincluding pump or the like while the motor 4 is connected to the drivecircuit which supplies control current.

Then, the coolant is supplied to the inlet duct 26, and spouts from thenozzle 27 through the inlet passage 25, the nozzle chamber 17, the ports24 and the coolant passage 23. By rotating the output shaft 30 of themotor 4, the rotation angle of the hollow shaft 18 connected to theoutput shaft 30 can be controlled. Accordingly, the angle of the nozzle27 can be adjusted which enables the coolant to be directed in anydesired directions. Here, it is also possible to omit the nozzle chamber17 arranged within the housing 14. With this configuration, the coolantcan be supplied directly from the inlet passage 25 to the ports 24 ofthe hollow shaft 18.

When it is necessary to adjust the initial position of the rotationangle (zero adjustment) of the hollow shaft 18, that is, the outputshaft 30 of the motor 4, a hall element (not shown) may be installed tothe hollow shaft 18 or the output shaft 30. Based on the detectedposition of the rotation angle, the zero adjustment can be performed.Alternatively, the zero adjustment can be performed by limiting therotation range of the nozzle 27 with a stopper. The nozzle 27 is rotateduntil it is abutted to the stopper and, based on the position where thenozzle 27 is abutted to the stopper, the zero adjustment is performed.

Due to the above configuration, the rotation angle of the nozzle 27 canbe adjusted in accordance with the change of the tool end position aftera tool change in the automatic machine tool, or in accordance with thechange of the distance between the nozzle and the processing position asthe machining process advances. Thus, the coolant can be appliedaccurately to the specific processing position. Here, since the steppingmotor is used as the motor 4, an open-loop control becomes possible.Compared with a case of a closed-loop control using a servo-motor, it ispossible to further simplify the drive circuit of the motor.

When controlling the rotation angle of the nozzle 27, besides adjustingthe nozzle angle for directing the coolant accurately to the cuttingarea, the nozzle 27 may be intentionally swung in a wide angle so thatcoolant can effectively sweep away the chips in the cutting area.Further, the rotation of the nozzle may be performed at a constant speedor a variable speed. Still further, by using the stepping motor as themotor 4, the control codes of NC machine tools for tool change or toolspecification (that is, M codes or T codes) become usable as controlsignals of the motor 4. Accordingly, this makes possible to control therotation angle of the nozzle 27 to track the processing area, therebycontributing to simplify the control circuits of the coolant applicationdevice.

By being able to flow coolant into the coolant passage 23 providedwithin the hollow shaft 18 which rotates the nozzle 27, theminiaturization of the coolant application device 1, especially, thedimensional reduction in its axial direction becomes possible. Moreover,by eliminating portions to be sealed as much as possible, drip-proofproperties and dust-proof properties are notably enhanced. Further, byconfiguring the cover 6 as a detachable part, it becomes possible toindividually replace or fix the housing 14 or the motor 4 even if one ofthem fails. Ease of maintenance can be thus achieved.

Next, the second embodiment of the present invention will be explainedwith reference to FIGS. 6 and 7. Here, identical parts recited in thefirst embodiment of the present invention is identified with the samereference numerals, and only parts not described in the first embodimentwill be explained in details.

As shown in FIGS. 6 and 7, in a coolant application device 40, thehollow shaft 18 of the housing 14 and the output shaft 30 of the motor 4of the first embodiment are integrally formed to each other so as toconfigure a hollow motor shaft 41. As shown in the example of FIG. 7,the hollow motor shaft 41 is installed in the motor 4 in advance, and isthen inserted into the housing 14. Alternatively, the hollow motor shaft41 may be installed into the housing 14 in advance, and then insertedinto or press-fitted to the motor 4. Due to this structure, the coolantapplication device of the second embodiment will enjoy the advantageouseffects identical with the first embodiment.

What is claimed is:
 1. A coolant application device, comprising: ahousing having a large diameter bore portion and a small diameter boreportion; a guide member fitted into the large diameter bore portion; anozzle that spouts coolant; a hollow shaft that has a coolant passagetherein and is connected with the nozzle, the hollow shaft beingrotatively and fluid-tightly inserted into the housing; a motor that hasan output shaft and adjusts a rotation angle of the nozzle to direct thecoolant to a desired angle; a plurality of ports that are arranged at alateral wall of the hollow shaft and communicate with the coolantpassage; and an inlet passage that is arranged in the housing andcommunicates with the coolant passage through the plurality of ports,wherein: a nozzle chamber is formed in the large diameter bore portionbetween the small diameter bore portion and the guide member, theplurality of ports are located in the nozzle chamber, and the nozzlechamber is configured to be wider than the inlet passage.
 2. A coolantapplication device as recited in claim 1, wherein the hollow shaft isfurther provided with a joint configured to transmit rotation from theoutput shaft of the motor to the hollow shaft.
 3. A coolant applicationdevice as recited in claim 2, wherein the joint has a double-faceconfiguration.
 4. A coolant application device as recited in claim 1,wherein the motor and housing are adapted to be installed in a box-shapecase main body of a case of the coolant application device, the motorand housing being utilizable while in the case.
 5. A coolant applicationdevice, comprising: a housing having a large diameter bore portion and asmall diameter bore portion; a guide member fitted into the largediameter bore portion; a motor with a hollow motor shaft made of asingle individual piece, the hollow motor shaft being provided with acoolant passage therein and being rotatively and fluid-tightly insertedinto the housing; a nozzle being connected with the hollow motor shaft,a rotation angle of the nozzle being adjustable by the motor to directcoolant to a desired angle; a plurality of ports that are arranged at alateral wall of the hollow motor shaft and communicate with the coolantpassage; and an inlet passage that is arranged in the housing so as tocommunicate with the coolant passage through the plurality of ports,wherein the hollow motor shaft is configured to allow the coolant topass through therein, wherein a nozzle chamber is formed in the largediameter bore portion between the small diameter bore portion and theguide member, wherein the plurality of ports are located in the nozzlechamber, and wherein the nozzle chamber is configured to be wider thanthe inlet passage.
 6. A coolant application device as recited in claim5, wherein the motor and housing are adapted to be installed in abox-shape case main body of a case of the coolant application device,the motor and housing being utilizable while in the case.